Pathogenic microorganisms have major impacts on human lives. Rapid and sensitive diagnostic tools are urgently needed to facilitate the early treatment of microbial infections and the effective control of microbial transmission. CRISPR-Cas13 employs programmable RNA to produce a sensitive and specific method with high base resolution and thus to provide a novel tool for the rapid detection of microorganisms. The review aims to provide insights to spur further development by summarizing the characteristics of effectors of the CRISPR-Cas13 system and by describing the latest research into its application in the rapid detection of pathogenic microorganisms in combination with nucleic acid extraction, isothermal amplification, and product detection.

With the alarming surge in COVID-19 cases globally, vaccination must be prioritised to achieve herd immunity. Immune dysfunction is detected in the majority of patients with COVID-19; however, it remains unclear whether the immune responses elicited by COVID-19 vaccination function against the Omicron subvariant BA.2. Of the 508 enrolled patients infected with Omicron BA.2, 102 were unvaccinated controls, and 406 were vaccinated. Despite the presence of clinical symptoms in both groups, vaccination led to a significant decline in nausea or vomiting, abdominal pain, headache, pulmonary infection, and overall clinical symptoms and a moderate rise in body temperature. The individuals infected with Omicron BA.2 were also characterised by a mild increase in both serum pro- and anti-inflammatory cytokine levels after vaccination. There were no significant differences or trend changes between T- and B-lymphocyte subsets; however, a significant expansion of NK lymphocytes in COVID-19-vaccinated patients was observed. Moreover, the most effective CD16^brightCD56^dim subsets of NK cells showed increased functional capacities, as evidenced by a significantly greater IFN-γ secretion and a stronger cytotoxic potential in the patients infected with Omicron BA.2 after vaccination. Collectively, these results suggest that COVID-19 vaccination interventions promote the redistribution and activation of CD16^brightCD56^dim NK cell subsets against viral infections and that they could facilitate the clinical management of patients infected with Omicron BA.2.

Thirty-five serotype K1 hypervirulent Klebsiella pneumoniae (K1-hvKP) isolates collected from a Chinese hospital during the whole year of 2017 were evaluated to characterize the prevalence of the plasmid-mediated quinolone resistance (PMQR) genes. In total, 18 (51.4%) isolates were detected to carry PMQR genes, and the most frequently detected gene was qnrS1 (37.5%), followed by aac(6′)-Ib-cr (15%) and qnrB4 (2.5%). Remarkably, some qnr -carrying strains had only a single or more quinolone resistance-determining region mutations in GyrA or ParC, and most exhibited high-level ciprofloxacin resistance. However, only 11.4% (4/35) isolates were resistant to quinolones. Furthermore, 34.3% (12/35) carried extended-spectrum β-lactamase (ESBL) genes, but only 14.3% (5/35) exhibited ESBL phenotype. The most prevalent virulence genes were mrkD (100%, 21/21), followed by magA (97.1%, 34/35), wabG (97.1%, 34/35), rmpA (97.1%, 34/35), aerobactin (94.3%, 33/35), kfuB (94.3%, 33/35), ycf (91.4%, 32/35), iutA (91.4%, 32/35), rmpA2 (62.9%, 22/35), wcaG (62.9%, 22/35), ybtS (51.4%, 18/35), allS (45.7%, 16/35), and iroN (22.9%, 8/35). Multilocus sequence typing (MLST) analysis assigned the 35 K1-hvKP isolates into 5 sequence types (STs), with ST23 encompassing 77.1% of the strains. Pulsed field gel electrophoresis (PFGE) typing showed that strains closely related by MLST clustered in major PFGE clusters, of which cluster A accounts for 16 ST23 isolates and cluster B includes 11 ST23 isolates. The analysis of the transconjugants showed decreased susceptibility to quinolones and revealed a cotransfer of bla _CTX-M-15 with the qnr S1 alleles. Cumulatively, our findings showed that the PMQR-producing K1-hvKP strain is covertly spreading even when K1-hvKP is rarely resistant to fluoroquinolones (FQs) according to the Clinical and Laboratory Standards Institute criteria. It is therefore critical to continuously monitor the PMQR-producing K1-hvKP epidemiology and minimize potential risks from FQ-resistant K1-hvKP.

Progression of liver failure to coma is a dynamic process. Its prognosis depends primarily on early diagnosis, real-time monitoring of the disease, and appropriate therapy. Current detection methods and repeated blood sampling do not effortlessly meet the clinical requirements. This pilot study aimed to assess the potential of exhaled breath analysis by extractive electrospray ionization mass spectrometry (EESI-MS) as a noninvasive clinical tool to diagnose and provide real-time monitoring of liver failure. A total of 24 healthy controls, 20 chronic hepatitis B patients, and 20 liver failure patients were enrolled in this study. Patients were diagnosed prior to exhaled breath collection; serological biochemical indicators and clinical characteristics were recorded. Exhaled breath samples were detected by EESI-MS; principal component analysis and partial least square discriminant analysis was used to process the final data. Twenty-two mass-to-charge ratio (m/z) values differed significantly between liver failure patients and healthy controls (variable importance plot (VIP)>3.5, P＜0.001), and eight metabolites were identified to be 1-butylene, acetone, glycolaldehyde, isoprene, butanone, 2-ethylacrylic acid, ethylmethylacetic acid, and 2,3-octanedione. Four m/z values differed significantly between liver failure and chronic hepatitis B patients (VIP > 3.5, P＜0.001) and 2 metabolites were identified to be isoprene and glycolaldehyde. Exhaled breath analysis may be valuable as a noninvasive clinical tool to diagnose and provide real-time monitoring of liver failure.